The EA one that I purchased is so easy to fool on expert, and I love playing connect 4, so I'm wondering which has the most difficult setting available?
The game has been "solved" and any app that loses to a human on its highest difficulty is just sad. Thats EA for you.
Maybe it's because they don't want the hardest difficulty to be impossible? It's easy to make it impossible, but hard to make the AI better other than making the game impossible.
Have you tried Finger Arts' "4 in a Row"? I think it's a pretty good version of connect 4, and I don't think it is easy to beat.